Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int a[105][105] = {0};
int ar[105][105] = {0};
int ac[105][105] = {0};
int rowr[100000] = {0};
int colr[100000] = {0};
int rowc[100000] = {0};
int colc[100000] = {0};
int rr = 0;
int cr = 0;
int rc = 0;
int cc = 0;
int check(int b[105][105], int n, int m) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      if (b[i][j] != 0) return (1);
  return (0);
}
int solver(int ar[105][105], int n, int m) {
  for (int i = 0; i < n; i++) {
    int min = 99999;
    for (int j = 0; j < m; j++)
      if (ar[i][j] < min) min = ar[i][j];
    if (min) {
      for (int k = 0; k < min; k++) rowr[rr + k] = i + 1;
      rr += min;
      for (int j = 0; j < m; j++) ar[i][j] -= min;
    }
  }
  for (int i = 0; i < m; i++) {
    int min = 99999;
    for (int j = 0; j < n; j++)
      if (ar[j][i] < min) min = ar[j][i];
    if (min) {
      for (int k = 0; k < min; k++) colr[cr + k] = i + 1;
      cr += min;
      for (int j = 0; j < n; j++) ar[j][i] -= min;
    }
  }
  return (rr + cr);
}
int solver1(int ac[105][105], int n, int m) {
  for (int i = 0; i < m; i++) {
    int min = 99999;
    for (int j = 0; j < n; j++)
      if (ac[j][i] < min) min = ac[j][i];
    if (min) {
      for (int k = 0; k < min; k++) colc[cc + k] = i + 1;
      cc += min;
      for (int j = 0; j < n; j++) ac[j][i] -= min;
    }
  }
  for (int i = 0; i < n; i++) {
    int min = 99999;
    for (int j = 0; j < m; j++)
      if (ac[i][j] < min) min = ac[i][j];
    if (min) {
      for (int k = 0; k < min; k++) rowc[rc + k] = i + 1;
      rc += min;
      for (int j = 0; j < m; j++) ac[i][j] -= min;
    }
  }
  return (rc + cc);
}
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) {
      cin >> a[i][j];
      ar[i][j] = a[i][j];
      ac[i][j] = a[i][j];
    }
  if (solver(ar, n, m) < solver1(ac, n, m)) {
    if (check(ar, n, m) == 0) {
      cout << (rr + cr) << endl;
      for (int i = 0; i < rr; i++) cout << "row " << rowr[i] << endl;
      for (int i = 0; i < cr; i++) cout << "col " << colr[i] << endl;
    } else
      cout << "-1" << endl;
  } else {
    if (check(ac, n, m) == 0) {
      cout << (rc + cc) << endl;
      for (int i = 0; i < rc; i++) cout << "row " << rowc[i] << endl;
      for (int i = 0; i < cc; i++) cout << "col " << colc[i] << endl;
    } else
      cout << "-1" << endl;
  }
  return (0);
}